Air heating furnace



L. LEE.

AIR HEATING FURNACE.

APPLLcATloNjFILED MAY22.1918.

Patented Oct. 21,1919.

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L. LEE.

A111 HEATING FUHNACE.

APPLICATION HLED MAY22,19ia.

1 3 1 9, 65 4: Patented Oct. 21, 1919.

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uUNITED STATES PATENT' OFFICE;

LEIF LEE, 0F YOUNGSTOWN, OHIO, ASSIGNOR TO THE YOUNGSTOWN SHEET & TUBECOMPANY, OF YOUNGSTOWN, OHIO, A CORPORATION OF OHIO.

AIR-HEATING FURNACE.

Application led May 22, 1918.

T 0 all whom t may concern:

Be it known that I, Lnrr Lun, a citizen of the United States, residingat Youngstown, in the county of Mahoning and State of Ohio, haveinvented a new and useful Improvement in Air-Heating Furnaces, of

which the following is a full, clear, and eX- act description, referencebeing had to the accompanying drawings, forming part of thisspecification, in which- Figure 1 is a sectional plan view of a furnaceembodying my invention the section being taken on the line I-I of lig.2.

Fig. 2 is a transverse section taken on the line-IIH-II of Fig. 1.

Fig. 3 is a partial longitudinal section taken on the line III-III ofFig. 1, and

Fig. 4 is a detail sectional view.

My invention has relation to air heating furnaces; and is designed toprovide a 'furnace in which air may be rapidly heated in large volume.Also to provide a furnace of this character having a novel arrangementof the air heating elements and possessing other advantages, some ofwhich are hereinafter pointed out.

In the accompanying drawings I have illustrated my invention as appliedto a thaw house for thawing out frozen cars of material, but I desire itunderstood that my invention is not limited to this purpose, but that itmay be applied for heating air for any desired purpose.

In these drawings, the numeral 2 designates the walls of the furnace andthaw house, of any usual or suitable construction; and 3 designates thewalls of one of my improved air-heating furnaces with which the thawhouse is equipped.

This furnace is provided with an inclosed heating chamber 4 havingtherein a plurality of air heating and conducting pipes 5 which are ofinverted U-form, the pipes being placed in bank in this chamber withsuiiicient opening or spaces between them to admit of the relativelyfree circulation of a gaseous heating medium. These pipes are secured attheir lower ends in suitable header plates 6, which can be made insections and readily removed. Preferably each pipe has its endsseparately removably seated in these header plates, as indicated at 7 inFig. 4, whereby any defective pipe may be readily removed and replaced.The roof of Specification of Letters Patent.

Patented Oct. 21, 1919.

serial No. 235,943.

the heating chamber 4 may be conveniently 'formed of a series of spacedI-beams 8, the spaces between which are filled with curved sheets 8,acting as arches, and covered with sand, as indicated at 8b (Fig. 8) andwhich can be readily removed to permit the removal of said arches. Anyother suitable construction may, however, be employed which is of acharacter to permit of ready access to the heating chamber and pipes.

The heating pipes 5 are arranged in the heating chamber at the sides ofand above a central flue'Q, which forms an air supply chamber, which atthe rear end of the furnace opens downwardly into an equalizing chamber10 extending the full length of and below the heating chamber, centrallythereof. The inlet ends of the pipes 5 communicate with this equalizingchamber and receive the air to be heated directly therefrom. Air issupplied to the :due 9 from any suitable source such as the fan orblower 11. The opposite ends of the pipes 5 open downwardly into a hotair chamber 12 which, in turn, is shown as opening into a lower hot airduct 13, from which the hot air is taken off for use at the desiredpoint or points.

The heating medium may consist of combustion or waste gases fromindustrial furnaces, such as open hearth furnaces, heating furnaces,glass furnaces, boiler furnaces, etc., such gases being suitablyconducted into one side of the heating chamber 4. In the embodiment ofmy invention which I have illustrated, I have shown the furnace ashaving three combustion chambers 14 arranged at one side of the heatingchamber, and communicating therewith by means of the openings 15 whichenter the base of the heating chamber through one of, the side walls.These combustion chambers may be fuel fired, but are shown as providedwith grates 16, or they may be fired by gas or oil, as indicated at 17.Each of the combustion chambers is provided with a plurality of cold airinlet openings 18 which can be controlled by hand by means of damperbricks or other suitable means so as to regulate the amount of cold airwhich will enter. The products of combustionrmiXed with this cold airpass to the openings 15 through checker-work 19, which thoroughly mixthe gases and air before they reach the pipes. In this way thetemperature of the combustion Agases is reduced to such an extent thatthe pipes will not be injured. These pipes are preferably of steel.

20 designates a baffle wall placed at that side of the air supply flue 9which is nearest the openings 15 and which is arched over the top ofsaid flue, this baille acting to cause a proper circulation of thecombustion gases around the hot pipes. The waste gases leave theheating' chamber at the opposite lower side portion through openings 21.These openings are provided with individual outlet connections 22communicating with. the 'common flue 23 and each connection 22 ispreferably provided with a separate regulating damper or valve 24. Thewaste flue 28 may, as shown, be connected with the inlet of a suctionfan 25 whose exhaust is connected` with a short stack 26; or the llue 23may be led directly to a draft stack.

This suction or exhaust fan 25 is preferably connected eitherindirectly, or directly, as shown, with the blower 11, so that when theblower is stopped the exhaust fan will stop simultaneously, thusshutting off the draft the moment the air sup-ply stops. In this mannerburning out of the heating pipes is prevented. I may also provide anysuitable regulating device of well known character, which, where gas isused for fuel, will shut off the supply of gas; or which, in the case ofsolid fuel, will regulate the air supply to the grates. Regulators ofthis character, such as thermostatic regulators with the thermostaticelement located in the heating chamber near the openings 15, may be usedfor this purpose. Or regulators controlled by the pressure of thedischarged air may also be employed.

To further protect the pipes 5 adjacent to the openings 15 so that theywill not be subjected to too high a teniperature of the contactinggases, they may be surrounded at this end portion by suitable protectingsleeves 27.

The llue 9 leading from the blower is provided with a suitable damper28; and the exhaust flue 2S is also shown as provided with a damper 29.

In the application of my invention which I have shown and in which theair is heated for the purpose of supplying` hot air to a car thawingchamber, the heating furnaces, or as many of them as may be necessary,are arranged above the thaw room 30. The hot air is taken from the hotair duct 13 and supplied to this thaw room 30 through any suitablesystem of pipes 31. The ceiling 32 of the thaw chamber is shown asperforated, so that the hot air, after passing through said chamber,will rise into the air space below the furnace, and pass throughsuitable openings 33 in the framing back to the ducts 34 and into theeyes of the fan 11. Ther dampers 35 control the passage of air fromthese return ducts into the fan. In this manner the warm air afterpassing through the thaw room can be returned to the fan for re-use.

The provision of the air equalizing chamber 10 causes air to enter allthe heating pipes at substantially equal pressure. By

' )assino' the air through these relativel f' small pipes it getsthoroughly heated, as each particle or molecule of air comes into moreor less contact with the heating surfaces. The arrangement of theopenings by which the heating medium enters and leaves the heatingchamber is such as will, in connection with the baille 20, cause themaximum amount of the heating surfaces of the pipes to be exposed to theheating action of the gases. The provision of the separate outletconnections leading to the stack flue, each connection having its owndamper, enables an even draft to be obtained throughout the whole lengthof the heater.

It will be noted that the heating pipes are held at their ends only, andowing to their U-shape are free to individually expand and contractwithout injury thereto.

38 indicates a cleaning out line into which ash, etc., may fall from thechecker-work 19 and from which such ash can readily be removed by meansof suitable doors 39.

As herein indicated the particular embodiment of my invention which Ihave shown and described, is illustrative only and I do not desire to belimited thereto. Obviously the particular construction will dependlargely upon the purposes for which the air is to be heated and theparticular character of the heating` medium which is employed.

I claim:

1. Air heating apparatus, comprising a heatingchamber having` therein aplurality of inverted U-shaped air heating pipes, said pipes beingarranged in concentric series or banks extending` longitudinally in thechamber, a combustion chamber arranged at one side of the heatingchamber, and a mixing chamber intermediate the combustion chamber andthe heating chamber and communicating with both of said chambers, saidmixing chamber having meanstherein for causing the products ofcombustion from the heating chamber to be mixed with relatively cold airbefore they are delivered to the heating chamber, ysubstantially asdescribed.

2. Air -heating apparatus comprising a heating chamber having invertedU-shaped heating pipes arranged therein in bank, means for causing acirculation of the air to be heated through said pipes, a combustionchamber having1 cold air inlet openings and communicating` with theheating chamber, and means for mixing thecold air and products ofcombustion as they pass from the combustion chamber into the heatingchamber; substantially as described.

3. Air-heating apparatus comprising a heating chamber having invertedU-shaped heating pipes arranged therein in bank, means for causing acirculation of the air to be heated through said pipes, a combustionchamber having cold air inlet openings and communicating with theheating chamber, and means for mixing the cold air and products ofcombustion as they pass from the combustion chamber into the heatingchamber, said means comprising checkerwork; substantially as described.

4. Air-heating apparatus comprising a heating chamber, a plurality ofU-shaped air heating pipes arranged therein in bank, au air supplypassage extending centrally of the bank of pipes, an equalizing chamberconnected to said flue and with which said pipes communicate at one end,and a hot air duct into which said pipes discharge at their oppositeend; substantially as described.

5. Air-heating apparatus comprising a heating chamber having a bank ofheating pipes therein, means for causing a circulation oi the air to beheated through said pipes, means for introducing a heating medium intosaid chamber atone side thereof adjacent to the lower ends of saidpipes, a plurality of separate waste gas outlets at the opposite side ofsaid chamber adjacent to the opposite lower ends of said pipes', a draftflue with which said outlets are connected, and damper means in saidflue and also in said outlet connection; substantially as described.

6. Air-heating apparatus comprising a heating chamber having a bank ofinverted U-shaped heating pipes therein, means for causing a circulationof the air to be heated through said ipes, means` for introducing aheating medium into Jehe hea'tin chamber, said heating chamber having ap urality of outlet connections for the heating medium, Valve means forseparately controlling said connections, a common iue into which saidconnections lead, and an exhaust fan connected to said flue;substantially as described.

7. Air-heating apparatus comprising a heating chamber having a pluralityol U- shaped air heating pipes arranged in bank therein, a blower forforcing the air through said pipes, means for circulating a heatingmedium in the heating,chamber around said pipes, an exhaust fanconnected to the Waste gas outlets of said heating chamber, and adriving connection between the blower and the exhaust fan; substantiallyas described.

8. Air-heating apparatus, comprising a heating chamber having therein aplurality of heating pipes arranged in bank, a fan for causing acirculation of the air to be heated` through said pipes, a combustionchamber for supplying a heating medium to the heating chamber, and a fanarranged to eii'ect a circulation of the heating medium through saidchamber, the two fans having a common driving connection, substantiallyas described.

9. Air-heating apparatus, comprising a heating chamber having aplurality of inverted U -shaped heating pipes arranged therein in bank,means for causing a circulation of the air to be heated through saidpipes, a combustion chamber, and a mixing chamber' intermediate thecombustion chamber and the heating chamber and through which theproducts of combustion pass on their way to the heating chamber, saidmixing chamber having means for mixing relatively cold air with theproducts of combustion and thereby reduce their temperature and increasetheir volinne, substantially as described.

Inv testimony whereof, I have hereunto set my hand.

LEIF LEE.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

